Twinkle Toes is Eileen's ballet dancing alter-ego, first shown in Regular Show: It's Just A Regular Movie. What made Eileen into "Twinkle Toes" was when she was dancing ballet in the Regular Show episode, "TGI Tuesday". She is known to be a fashionable ballerina. The reason why people call Eileen "Twinkle Toes" is that she is a very good dancer, and she is a good ballerina.

As said above, Eileen is a short mole with tan fur. She has red glasses and wears the same uniform as Margaret, although in "Do Me a Solid", she wears a pink shirt with ruffles around the neck and shoulders and a blue skirt. She has a small light brown tail and brown hair tied into a side ponytail. In Brain Eraser, her ponytail was on the right side, in Do Me a Solid, her ponytail was moved to the left side. In Brain Eraser, she didn't have white in her glasses, as seen down below, but in Do Me a Solid, she did. In "First Day," Eileen appears very different than usual. She only had pupils for eyes like she did in "Brain Eraser" except her glasses were pointed down like reading glasses and she wore a purple shirt with a green oval in the middle with a small green skirt. Also, in "Camping Can Be Cool," she was wearing a light burgundy hoody and light army green shorts. Eileen never wears shoes in any episode just like Mordecai, Rigby, and Margaret. She and Margaret wear clothes, unlike Mordecai and Rigby. Eileen looks surprisingly human. Her eyes are small and squinted.

"As Twinkle Toes", that what they call her in the movie, appears to wear glasses, a purple hoodie sweater, light blue capri tights, "Twinkle Toes/Bella Ballerina" shoes from Skechers, and a pink tutu, but no scrunchie. She does have brown hair. She is even a mole (who looks surprisingly human), that is what Eileen was her whole life.

Rigby has been Elieen's crush ever since "Do Me a Solid". At first Rigby didn't feel the same way and saw her as a pest. However, as the series progresses, it seems as though Rigby is getting used to hanging around Eileen. JG Quintel has noted this as an example of Rigby's growth as a character.2 ]

"Camping Can Be Cool" was probably the first time they had real relations. At first, after they lose the matches, Rigby and Mordecai argue for a bit then Eileen starts a fire the old fashion way. Rigby compliments her by saying "Yeah, that was kinda cool". Eileen blushes then Rigby, unsure of himself, creates a distraction by throwing the package of hot dogs at her. Then, later that night, they are seen playing video games on a log. When Eileen corrects Mordecai on the constellation, Rigby compliments her again, causing both of them to laugh. When they are running away from the Stag-Man, Eileen throws a rock in Margaret's car window, later when they are returning home Rigby admires Eileen by saying, "And you totally busted Margaret's window open with a rock".

In "Diary", while Rigby was revealing all of his secrets, he mentions that he thinks that "Eileen looks hot without her glasses on." It is found out the next day that Eileen was at Margaret's apartment, watering her plants, and heard him. She shows up to work without her glasses off (catching Rigby by surprise), but ultimately ends up running into a table.

In "In the House ", when Rigby is turned into a house by the wizard, a picture of Eileen can be seen on the mantlepiece in the living room.

"One Pull Up" has a lot of interaction between Eileen and Rigby and possibly hints Rigby may like Eileen back. In this episode Eileen helps Rigby do a pull up and at the end of the episode Eileen and Rigby hug marking their first hug. Eileen also takes off her glasses again.

In Meteor Moves, although he is much more tolerant of her annoying lectures on astronomy, he is really annoyed by her constant babbling, while he is trying to see if Mordecai will kiss Margaret.

In Family BBQ, he and Eileen were seen playing cards together.

In "Merry Christmas Mordecai", Eileen throws a sweater party for the holidays while inviting everyone including Rigby, Mordecai, CJ, and Margaret. While Mordecai and CJ's relationship gets a little shaky because of Margaret's appearance during this episode, Eileen and Rigby's bond flourishes a bit more. The first time when you see a hint of this is when you see Rigby trying to wrap a gift for Eileen which turns out to be a mistletoe disco ball. The second small gesture occurs when Mordecai notices people kissing under the disco ball. So he decides to tease Rigby for being chicken for not kissing Eileen because of the mistletoe in her hair. So to prove that he wasn't chicken, Rigby kisses Eileen on the cheek. Judging by Eileen's reaction, they had both grown more comfortable around each other because he didn't shy away from kissing her and she didn't faint or go into a daze. She just blushed slightly. It also means Rigby holds the same crush Eileen holds on him.

In "I See Turtles", Rigby is seen giving Eileen a piggy-back ride. Later in the episode, when Eileen is sad about the capture of the turtles, Rigby gets mad and helps her free the turtles.

In "Dumped at the Altar", it was revealed that they have been secretly dating for months, confirming their relationship.

In "Dumptown USA," Rigby and Eileen are still seeing each other, but Rigby has Eileen dump him so he can go to Dumptown and rescue Mordecai. Eileen is reluctant at first, but then gets genuinely frustrated pointing out Rigby's faults, despite Rigby reminding her the dumping is not "for realsies." Upon his return from Dumptown, Rigby gets a call from Eileen, who is still mad at him, though Rigby again protests this was not a "for realsies" breakup.

In "The Eileen Plan ," Rigby is intimidated by Eileen's ambitious life plans and secretly goes back to high school to get his diploma in an effort to catch up with her, something he keeps secret. Eileen is upset that he repeatedly ditches her, but after tracking him down on a field trip, is impressed he did this for her, and tells Rigby she likes him for who he is. Rigby decides to continue working for his diploma for his own betterment.

In "Crazy Fake Plan ," Rigby is irate that Eileen always correctly guesses the surprise dates he plans for her, sometimes before he can even tell her. He develops an elaborate, circuitious plan involving numerous fake locations and a fake biker gang to throw her off. In the end, Eileen is very impressed with the surprise and Rigby's plan, and realizes she needs to not try to second-guess everything he plans.

In "Snow Tubing" Eileen is afraid to tell Rigby she is afraid to go snow tubing, due to a traumatic event as a child. She does everything to try to delay their trip to go snow tubing, but accidentally winds up with Rigby on the highest, most dangerous run just as the ski lifts close. Rigby is understanding about her fear and lets her know she can tell him these things, and they wind up having a good time after an action-packed trip down the mountain, which makes Eileen a giant fan of snow tubing.

In "Rigby Goes to the Prom", Rigby invites Eileen as his date to prom at his old high school, from which he's finally graduating. Eileen accepts, because no one asked her to prom when she was in high school. They have a great time at prom, though the evening turns dangerous when RIgby's dad angrily reclaims his car that Rigby's mom had loaned them, resulting in a chaotic near accident. Afterwards, Eileen is enthusiastic about having enjoyed an exciting prom night.

In "Rigby's Graduation Day Special", both herself and Rigby are graduating. During Rigby's graduation speech, she is listed as his inspiration. By the end of the episode, they are stuck in space together.

In "A Regular Epic Final Battle", after Rigby and her land on earth with the rest of the crew and reunite with their loved ones, Rigby kisses Eileen, making it their first kiss of the series.

In "Heroes Disbanded", She and Margaret arrived told the heroes where Mordecai and Rigby are? They had a date. Dib told Margaret and Eileen that Mordecai and Rigby had to go with Dan, Troll, Amanda, Randy and Howard to go their new home called New York and they won't be back for a long time. They had a very special connection. They'll always remember them and gave them a video message. If they watching this, Mordecai and Rigby can't come back to the park no more. Their date is cancelled. But they could still video date.

Eileen is Margaret's best friend at the Coffee Shop, where both of them work. The two get along well, and are always seen together (whenever Eileen is present). Both share a friendship with Mordecai and Rigby, sometimes talking about them. Eileen also took care of her apartment in "Diary", but Mordecai and Rigby didn't know until Margaret told them about it. Although they usually get along, in Meteor Moves she is a bit annoyed when Eileen follows up Rigby and Mordecai's creative rap with an un-catchy factual rap. In a sequel to the Regular Show: The Movie, Elieen is fifth one to be rescued by Margaret and her ice powers from Susan's Chaos

Eileen seems to be good friends with Mordecai. Like in "Camping Can Be Cool" he invited her and Margaret to go camping and they both encourage Margaret that camping can be fun. Her, Mordecai, Rigby and Margaret usually hang out together. As well in "Death Bear" where he tackled Death Bear into a wall to save her. However, Mordecai was quite annoyed with her constant babbling about astronomy in Meteor Moves, as well as the fact that she was in between Margaret and Mordecai, when Mordecai was planning to kiss Margaret. He is irritated when Eileen follows up Rigby and his creative rap with an un-catchy factual rap.

Eileen has interacted with Muscle Man once in "Do Me a Solid" when Eileen, Margaret, and uninvited Muscle Man were having ice cream sandwiches at the house. In "One Pull Up," she said "Muscle Man was in here earlier", hinting that he comes to the coffee shop often. In "TGI Tuesday," Muscle Man says "hello ladies...and Eileen", and he helps her, Mordecai, and Rigby invite people to Margaret's surprise party at the "Parkside de Lux."

Both Eileen and Starla seem to be friends as seen in "The Longest Weekend" with how the two of them were shown to interact with one another, however how good of friends or how long they have know each other is unknown.

In the movie, it was revealed that Eileen had a ballet-dancing flashback. Ever since she was a teenage girl in high school, she wanted to learn the moves of a ballerina, but fashionably. Margaret does dance ballet too, but Margaret's nickname doesn't have to be "Twinkle Toes". Eileen learned a lot of ballet dancing moves, which causes to make Eileen into a female fashionable ballerina, nicknaming her "Twinkle Toes".

In the Regular Show TV series, Eileen was not nicknamed "Twinkle Toes", but the first time in "TGI Tuesday" she was dancing like a ballerina, also freestyle dance, or something like that, it made YOU think that Eileen should be nicknamed "Twinkle Toes", especially in "Regular Show: It's Just A Regular Movie", which marks the first time Eileen's nickname was "Twinkle Toes".

In "Camping Can Be Cool," it is revealed that she's developed good camping skills because she got lost in the woods a lot.

She is allergic to duck dander, as revealed in "A Bunch of Baby Ducks."

Eileen usually doesn't wear shoes, mainly when she is at work. However, when she is seen wearing outfits other than her uniform, (around season 5) she starts to wear shoes more. In "Access Denied," "Tants" and "Portable Toilet," she wore red shoes. She also wore white shoes in "TGI Tuesday" and in "Play Date".

More casual outfits (like the hoodie) would be accompanied by her white shoes.

When wearing more dressier attire, (like her pink shirt with the white lace around the neck and her black dress) she would have her red ones on.

In "Brain Eraser," her glasses were clear inside and she had black frames. Afterwards, the insides were changed to white and the black frames were replaced with red ones. Look above for an image of Eileen in her debut.

Eileen likes to dance, revealed in "TGI Tuesday," she is seen dancing in both "free style" and ballet. Also, in "Video 101", she takes it a step farther and choreographs her own music video.

In "Tants," it is shown that she can sew pretty well, as she helps make Mordecai and Rigby replacement pairs of tants. It is also mentioned in "New Year's Kiss," when Rigby asks her what her New Year's Resolution is.

Several things about Eileen were revealed in the episode Video 101:

She attends college.

She also never failed a class before

Her last name is revealed to be Roberts.

She owns a car, and knows how to drive, despite her short size.

Eileen didn't own a television in her house, as mentioned in the episode "Play Date", until she won one in "Eileen Flat Screen".

In the episode "Take the Cake," it is shown that Eileen has exceptional baking skills.

In the episode "Skips in the Saddle", it is revealed that Eileen has a rock polisher.

Eileen used to have a roommate named Joanne that lived in her house, until she was forced to leave and Margaret took her place.

Eileen hides her house keys under a clay turtle on her front lawn.

She use to have a fear of snow tubing because of an accident she had as a child.

In Crazy Fake Plan she said that her mind is also a curse because she always figure out surprises quickly.